New inlet bridge appears to be on fast track


The project has been long delayed and even longer anticipated, but the construction phase for the new Indian River Inlet Bridge officially kicked into gear this week with formal announcement of a timetable for the $150 million project, slated to open to traffic by the summer of 2011, likely in late June or early July.

Design-build contractors Skanska USA Civil Southeast Inc. have been driving “test piles” in recent weeks, using impact hammers to push slender pre-cast concrete components 100 to 115 feet into the ground for data collection on the potential carrying capacity for the bridge piers. Those piers will eventually take the full weight of the new 2,600-foot-long bridge across the Indian River Inlet, 900 feet of which will hover over the Inlet itself.

The first of those tests went well, according to Delaware Department of Transportation (DelDOT) project manager Doug Robb, who participated in a presentation with Skanska officials on Tuesday, Feb. 10. He said the first test pile held up under a 1,800-ton test load.

“That’s a lot of load per pile,” he noted.

Once the test pile program is completed, likely by this summer, Skanska plans to begin the driving of some 284 “production” piles that will support the new bridge. Substructure will then be added atop the pylons, with steel beams, concrete deck components and then 240-foot-tall towers (pylons) bearing much of the eventual stress of the revised, cable-stayed design.

That design is akin to the Williams V. Roth Jr. Bridge over the Chesapeake & Delaware Canal, near Wilmington. But instead of the Roth bridge’s two towers in the center of the bridge, the new Inlet bridge will have two towers along either side of the bridge, each set of cables in a single plane, as in the Roth bridge.

In addition to removing bridge support structures from the water, the new design will increase the vertical clearance over the navigational portion of the Inlet from 35 feet to 45 feet. There will be two 12-foot-wide travel lanes, a 10-foot-wide outside shoulder and a 4-foot-wide inside shoulder in each direction. A 12-foot-wide sidewalk will also provide access – as well as a scenic overlook – on the east side of the bridge.

Public to get input on final design elements

A public workshop is planned – likely in March, according to Skanska’s Andrew Bing and DelDOT’s Tina Shockley – in which Skanska will solicit input from the public on design details such as the color of the cables, lighting styles for the pedestrian walkways and pylon legs, and the design for the tops of the pylons. The public will also be able to register their preferences in those areas online.

The public is being encouraged to keep updated on the project through DelDOT’s project Web site at http://www.deldot.gov/information/projects/indian_river_bridge/, which is being updated almost daily with information and images.

They can also attend the monthly meetings of the Construction Advisory Group, which are set to resume this month. The CAG meetings are designed to provide updates to those most affected by the construction, such as nearby homeowners, businesses, Chambers of Commerce and users of the state park, but all are welcome to attend. Minutes of the meetings will also be posted on DelDOT’s Web site.

Aggressive schedules to bring project to completion

DelDOT and Skanska officials noted Tuesday that the anticipated impact of the project on traffic in the area of the existing bridge is expected to be minimal for the duration of the project and non-existent for much of it.

Since the project will be built alongside the existing bridge, the only anticipated traffic impacts are periods when large shipments of materials might require a temporary lane closure or when workers are working in close proximity to the existing bridge and roadway. No traffic impact is expected in 2009. Fishermen are not expected to see direct impacts of the project until mainspan construction in 2010.

But, already, modifications to the original embankments leading to the bridge site have been made, adjusting for the change to a longer over-land span after the embankments were found not to have settled properly. State officials have not yet released the results of an investigation as to where the fault for that problem lies.

As the heavy construction phase for the project begins to ramp up, Skanska project manager Jay Irwin noted that the final design details of the bridge are still being created. But he said Skanska was pleased that DelDOT’s bidding process for the project had “made it easy to design.”

“They allowed us to get it to an advanced point in the tender phase,” he said, using a word for the ongoing design process that can regularly be heard in connection to Skanska’s work on the project: “aggressive.”

Irwin said the aggressiveness of the construction schedule – which is anticipated to beat DelDOT’s original timetable, with completion as early as spring of 2011 – would only be enhanced by a little healthy competition between the two separate crews that will be building the bridge from the north and south sides of the inlet.

In addition to the 16 or 17 “design deliverables” that Skanska is using as intermediate goals for the project, Irwin said the project is being broken up into “two separate and distinct projects” with duplicate teams working to the north and south of the inlet.

“It creates constructive competition that leads to very healthy construction,” Irwin suggested of those separate teams, which will be competing not only to do the job quickly but at high quality.

Skanska will be bringing in pre-cast concrete components for the bridge, such as the piles, from its Cape Charles, Va.-based subsidiary, Bayshore Concrete Products. Irwin said Skanska’s business structure made them an ideal choice for the project.

“We’re a large international company with a local flair,” he said, pointing to the company’s corporate offices in Cape Charles, about three hours away from the worksite. “We were pleased to be selected, and we want to be partners to the local community, DelDOT and the public.”

“We’re excited to have Jay and Skanska working with us,” added Robb. “In the past five or six months, we’ve developed a good relationship, and I have all confidence that we will get this project done on time and in budget, and it will last a long time.”

The estimated minimum lifespan of the new bridge is 100 years.

Existing bridge among most monitored in U.S.

While work was under way on its replacement, Robb on Tuesday reiterated DelDOT assurances about the safety of the existing bridge, noting that while the scour holes at the base of the supports of the bridge continue to be DelDOT’s primary focus, “The good news is that we’re seeing stabilization of the erosion.”

He said the fast erosion seen in the 1980s had apparently been mitigated by the subsequent placement of large stone rip-rap as armor for the piers in the inlet. “They’re holding up very well, despite the recent storms,” he said.

Ongoing monitoring of the bridge’s safety includes inspection by dive teams on a six-month rotation, telemetric surveys and soundings, a sonar system attached to the bridge’s foundations and, to ensure there are no sudden changes, tilt sensors on top of the bridge’s piers.

“We believe this is one of the most-monitored bridges in the country now,” Robb emphasized Tuesday, saying that one of the first things DelDOT does after a coastal storm is to inspect the bridge. “We feel very good about its condition. We’ll do whatever we need to do to protect the travelling public. … And they will close the bridge if necessary.”

While he said no updated estimates of the existing bridge’s safe lifespan – variably listed in the past as between 2008 and 2015 – have been made, due to the variables involved, Robb said the aggressive schedule to get the new bridge in service was part of the state’s focus on continued public safety. “[The foundations] are safe now, but they will not be safe forever,” he said Tuesday.

Timeline includes park enhancements

The construction timeline for the larger Indian River Inlet Bridge project includes not just construction of the bridge and its approaches but also park enhancements at Delaware Seashore State Park, which are anticipated to start in 2012.

Those improvements include: day-use facility improvements; campsite improvements, including a laundry facility; new and enhanced bathhouses; a park office; contact stations; additional recreational areas; new lighting and landscaping; handicapped access to the new bridge; and marina improvements.

Currently, the construction of the project has included some closures of the neighboring campgrounds that are expected to be in place for the next several years. Access for pedestrians to get to the beach and for fishermen will be maintained for most of the construction, Shockley said this week. Some restrictions are likely during some of the construction, she noted.

The bridge itself will be undergoing construction while associated projects are being bid out and contracted.

Robb said advertising for a separate contract to complete the approach roadways design was anticipated early in 2010. That construction is expected to take nine to 12 months, anticipated to start in late summer of 2010.

Once the bridge structure and roadways are complete and the roadways are tied in to the new bridge, the next phase of the project will be the demolition of the existing bridge, which is expected to start in late 2011.

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Inlet bridge construction timeline:
• Bridge design: 2008-2009
• Mobilization: winter 2008 to early 2009
• Concrete piles: winter 2008 to summer 2009
• Footings: summer 2009 to fall 2009
• Substructure abutments and piers for bridge approaches: summer 2009 to fall 2009
• Pylons: summer 2009 to summer 2010
• Bridge approach spans: winter 2009 to spring 2010
• Superstructure/cable stay: spring 2010 to winter 2010
• Bridge open to traffic: spring/summer 2011